An analysis apparatus is disclosed in Published Japanese translation of PCT international publication for patent application No. 10-504397 (WO96/09548) and so on, in which an analysis object set on the tracks of an analysis disc is traced and an image is obtained by using a compact disc for recording audio or video (hereinafter referred to as an optical disc) and the reproducing function of an optical disc drive for reproducing the disc.
To be specific, a typical optical disc drive is configured as shown in FIG. 9.
An optical disc 101 is rotationally driven in the direction of arrow C by a disc motor 102. A screw shaft 105 is rotationally driven by a traverse motor 104 so that a pickup 103 for irradiating the optical disc 101 with detection light and detecting reflected light moves in the radial direction (the direction of arrow A) of the optical disc 101.
The traverse motor 104 and the disc motor 102 are operated by a servo control circuit 106 according to the reproduction output of the pickup 103 in the following manner:
According to the reproduction output of the pickup 103, the servo control circuit 106 drives the traverse motor 104 so as to trace tracks composed of pits or grooves, etc., detects address information recorded on the tracks of the optical disc 101, and drives the disc motor 102 with a constant linear velocity (CLV control).
Further, the reproduction output of the pickup 103 is processed by a reproducing device 107, so that a sound signal or a video signal that serve as data recorded on the tracks are reproduced and outputted.
On the other hand, the analysis apparatus is almost identical to the typical optical disc drive in block diagram form. In the case of the analysis apparatus, as shown in FIG. 10, a mixture of a sample and a reagent corresponding to a test item is set on the optical disc 101 as an analysis object B in addition to a track 101a. In the case of the analysis apparatus, the servo control circuit 106 and the reproducing device 107 obtain an image of the analysis object B on the optical disc 101 as described below. The direction of an arrow on the track 101a indicates the tracing direction of detection light from the pickup 103.
Also in the case of an analysis disc, time information or the like composed of pits, grooves, etc. on the optical disc is formed according to the standards of conventional optical discs for recording audio or video, and thus the specific explanation thereof is omitted. Specific examples are Compact Disc System Description (commonly called Red Book standard) and Compact Disc Readable System Description (commonly called Orange Book standard).
The laser irradiation point of the pickup 103 controlled by the servo control circuit 106 traces the spiral tracks 101a of the optical disc 101. The tracks 101a have a pitch of 1.6 μm on the optical disc according to Orange Book standard. The pickup 103 traces 1, 2, 3, . . . , 8, . . . , in turn for each rotation of the optical disc 101.
That is, in the operations of the analysis apparatus, a portion of the analysis object B and a portion of the track 101a are alternately passed and traced. In the case of the analysis apparatus, the reproducing device 107 extracts only data of a portion of the analysis object B that is obtained by tracing, and reconfigures data, so that video or shape count is performed.
The analysis apparatus may detect and process light reflected from an optical disc in the same manner as a typical optical disc drive for reproducing an optical disc, and the analysis apparatus may detect and process light passing through an optical disc.
Absolute time is engraved as address information on a disc such as a CD and a DVD. The time information is composed of minutes, seconds, and frames. One second is constituted of 75 frames.
The recording system of the time information is broadly divided into the following two kinds: a system for recording data by changing a length of a pit such as EFM and a system for recording after a groove is snaked by FM modulation on a recording disc.
Even when the ordinary time information of the optical disc is used to construct a video signal or perform shape count in the analysis apparatus, analysis accuracy cannot be expected to improve for the following reasons:
In both of the optical disc drive and the analysis apparatus, existing address information recorded on an optical disc is used to search for a given position on the optical disc 101. However, when a minimum unit distance obtained from the address information is calculated based on the example of the typical optical disc having 75 frames per second, just 120 (cm)÷75 (frames)=1.6 (cm/frame) is obtained at the minimum because the disc has a linear velocity of 1.2 to 1.5 m/S. That is, accuracy only to 16 mm can be specified even in one frame serving as the minimum unit.
An analysis apparatus for a blood test requires accuracy enabling the detection of an object of about 10 μm in a small area of 5 square millimeters on the optical disc 101. However, when video processing is performed on an image of the analysis object B, which is read in time series by the pickup 103 tracing the tracks, to obtain an accurately read image shown in FIG. 11(b), only a read image shown in FIG. 11(a) can be obtained in the present state where the reproducing device 107 performs video processing according to the address information.
To be specific, the reproduced image has a displacement in the rotation direction C of the optical disc 101 as shown in FIG. 11(a) and has a value far from accuracy required for analysis of blood and so on. Thus, it is understood that the image is too rough to be used.
An object of the present invention is to provide an analysis apparatus which can perform shape analysis satisfying accuracy required for analysis of blood and soon, and a special analysis disc used for the same.